The “best interests” of the patient are widely seen as a cornerstone of medical practice. They are the explicit legal standard for medical care in the case of patients who lack capacity to consent to treatment.

The best interests of the individual patient have, of course, long been compromised for the sake of other potential patients—in infectious disease control for example. The question of the ethics of such compromise became a hot issue, for UK doctors, about fifteen years ago in the context of health care rationing. At that time the fact that there are insufficient resources to provide all patients, in all circumstances, with the best possible treatment became explicit. Faced with this uncomfortable truth, doctors tended to divide into two camps. Some wanted to play no role in decisions about resource allocation. They continued to be guided by the single ethic of each individual patient's best interests. However, “best interests” could be interpreted as “best” given the treatments that were made available by those who determined the allocation of resources. Others took the opposite approach: since choices had to be made as to the best use of available resources, doctors ought to be playing a significant role in making these choices.

This polarisation has softened over time. Doctors have become more at ease with the idea that some treatments are not, given the overall resources, cost-effective, even if they are the best available. Clinical guidelines increasingly are influenced by cost-effectiveness. To provide the best health care overall, within the available resources, doctors aim to provide good care for each individual patient, but they do not always provide the best care.